[2] Its eastern edge is marked by the 100-fathom (600 ft; 183 m) curve, which lies from 20 to 30 nautical miles (37 to 56 km; 23 to 35 mi) off the west coast of Palawan.

[2] To the west of the passage lies Dangerous Ground, a poorly surveyed and charted area of the southeastern South China Sea which includes numerous reefs, shoals, and rocks.

[4] During the northeast monsoon, between October and December, the passage tends to enjoy calmer weather than the area of the South China Sea to the west of Dangerous Ground.

[2] During the Pacific campaign of World War II, United States Navy submarines operated in the Palawan Passage to attack Japanese shipping.

On October 23, 1944, the first day of the Battle of Leyte Gulf, the U.S. submarines USS Darter (SS-227) and USS Dace (SS-247) attacked an Imperial Japanese Navy task force under the command of Vice Admiral Takeo Kurita as it passed through the Palawan Passage on its way from Brunei to the Sibuyan Sea and San Bernardino Strait.